1. Field of the Invention
The present invention relates to an expanding tool, and more particularly to a pipe end expanding tool having a simplified configuration for effectively operating or actuating an expanding mandrel to expand the hollow members or hollow workpieces and to retract the expanding mandrel from the expanded hollow members or hollow workpieces.
2. Description of the Prior Art
Typical pipe end expanding tools comprise an expanding mandrel slidably received in a tool body, and a handle pivotally attached to the tool body and having a cam device for directly engaging with the expanding mandrel and for moving or forcing the expanding mandrel forwardly to engage with and to expand the hollow members or hollow workpieces.
Normally, the expanding mandrel will include a conically tapering end movable forwardly to engage with a number of expanding wedges or segments and to move the expanding wedges or segments radially and outwardly in order to expand the hollow members or hollow workpieces.
For example, U.S. Pat. No. 2,999,529 to Rast, and U.S. Pat. No. 4,034,591 to Rothenberger disclose two of the typical pipe end expanding tools each also comprising a handle pivotally attached to a tool body and having a cam device for directly engaging with an expanding mandrel that is slidably received in the tool body and for moving or forcing the expanding mandrel forwardly to engage with and to expand the hollow members or hollow workpieces.
However, the expanding mandrel may only be moved forwardly to engage with the expanding wedges or segments and to move the expanding wedges or segments radially and outwardly to expand the hollow members or hollow workpieces. After the conically tapering end of the expanding mandrel has been forced into the expanding wedges or segments, it will be difficult to retract and to remove the expanding mandrel from the expanding wedges or segments.
U.S. Pat. No. 4,890,472 to Rothenberger and U.S. Pat. No. 5,046,349 to Velte disclose the other typical pipe end expanding tools each also comprising an expanding mandrel slidably received in a tool body, and a handle pivotally attached to the tool body and having a cam device coupled to the expanding mandrel with a rigid tongue or linking member for indirectly engaging with the expanding mandrel and for moving or forcing the expanding mandrel forwardly to engage with and to expand hollow members or hollow workpieces.
The expanding mandrel may also be selectively moved rearwardly by the handle after the conically tapering end of the expanding mandrel has been forced into the expanding wedges or segments. However, the rigid tongue or linking member is normally made or formed into a plate-like structure which includes a greatly reduced thickness and which may have a good chance to be bent and damaged or distorted when the cam device of the handle moves or forces the expanding mandrel forwardly to engage with and to expand the hollow members or hollow workpieces.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional pipe end expanding tools.